1. Field of the Invention
The present invention relates to non-reciprocal circuit elements, such as circulators and isolators, to be applied to transmitting and receiving systems or the like.
2. Description of the Related Art
FIGS. 13 and 14 show a known non-reciprocal circuit element. Specifically, FIG. 13 is an exploded perspective view of the known non-reciprocal circuit element, and FIG. 14 is a perspective view of a ferrite part of the known non-reciprocal circuit element.
Referring to FIGS. 13 and 14, the structure of the known non-reciprocal circuit element will now be described. A base 51, which is a synthetic-resin molded part, includes a recess 51a disposed at the center and a plurality of notches 51b disposed on the top surface of the base 51.
Three chip capacitors C1, C2, and C3 and a chip resistor R are housed in the notches 51b. 
First, second, and third central conductors 53, 54, and 55 formed of thin films are disposed on the top surface of a disc-shaped ferrite part 52.
The first, second, and third central conductors 53, 54, and 55 are stacked on one another with dielectric parts (which are not shown in these figures) formed of insulating thin films disposed therebetween. Portions of the first, second, and third central conductors 53, 54, and 55 intersect at an angle of 120°.
The ferrite part 52 is housed in the recess 51a. One end of the first central conductor 53 is wire-bonded to the capacitor C1. One end of the second central conductor 54 is wire-bonded to the capacitor C2. One end of the third central conductor 55 is wire-bonded to the capacitor C3.
Two magnetic discs 56 are disposed above and below the ferrite part 52. On the top surface of the upper magnetic disc 56, a first yoke 57 is disposed. On the bottom surface of the lower magnetic disc 56, a second yoke 58 is disposed. The first and second yokes 57 and 58 are connected to form a magnetic closed circuit.
The above mentioned known non-reciprocal circuit element has the first, second, and third thin-film central conductors 53, 54, and 55 disposed only on the top surface of the ferrite part 52. To arrange the first, second, and third central conductors 53, 54, and 55 on the ferrite part 52, wires must be used. This is unfavorable in terms of productivity and cost.
Since the above mentioned known non-reciprocal circuit element requires the chip capacitors C1, C2, and C3 and the chip resistor R, it is cumbersome to assemble these parts in place. The size of the non-reciprocal circuit element becomes large.